Pigs and people in China continue to fall ill from puzzling disease

Aug 5, 2005 (CIDRAP News) – Reports from China today put the number of human cases of the baffling disease spreading through pigs in several areas at high as 212, with some 134 people still hospitalized and at least 14 considered critical. The number of deaths so far stands at 38.

The causal agent of the illnesses, considered by most experts to be Streptococcus suis, has killed 644 pigs in the southwestern Sichuan province, according to a Reuters story today. One case has also been reported in Guandong province; whether that case is associated with the large Sichuan outbreak has not been determined. Hong Kong has had two cases that coincide with the Sichuan cases, but no association has been confirmed for those either.

Almost all of the people infected are farmers who had close contact with infected animals during slaughter. People can catch the animal-borne disease only when wounds or scratches come into direct contact with an infected animal or when they eat uncooked or undercooked meat from an infected animal.

Strict regulations aimed at containing the outbreak have been issued. Exports of pork products from Sichuan were halted last week. Rural farmers are asked to practice strict hygiene and are required to not slaughter, sell, or eat any pigs dying of the disease, according to the Chinese news agency Xinhua. Officials and farmers who fail to obey will be "punished severely by law," says an Associated Press (AP) story quoting the Chinese commerce ministry. Three officials have reportedly already been dismissed because of failure to enforce the new rules.

In Hong Kong, says a story in the Chinese business newspaper The Standard, infected pigs are to be buried in designated areas and then only after applying disinfectant to the carcass and wrapping or bagging it. Some farmers are reportedly refusing to comply. In Vietnam, the government has ordered an immediate halt to the import of pork products or live pigs from affected areas of China, according to Thanh Nien News.

The Chinese government listed S suis as a notifiable disease earlier this week, meaning that doctors encountering patients with suggestive symptoms are required to report them to the government.

Symptoms of the disease in humans include early flu-like symptoms of fever, nausea, and vomiting, followed by dizziness, confusion, difficulty breathing, weak and rapid pulse, bleeding under the skin, and in some cases coma and/or organ failure, says another Standard story. The disease course in the current cases is distinctive in that patients are dying very quickly after onset of the infection, in some cases within 2 hours, according to numerous reports.

The severe symptoms and rapid disease course are puzzling to expert observers, who are questioning whether some other factor may be at play, such as existence of a new, more virulent strain of S suis, coinfection with another agent, or another cause altogether. The World Health Organization (WHO), UN Food and Agriculture Organization (FAO), and World Organization for Animal Health (OIE) are all urging China to conduct more tests and/or seek outside help to clarify the situation.

Vaccines for swine are reportedly being manufactured in large quantities. No vaccine for humans is yet available.

China is the world's largest pork producer, and the Sichuan province is the largest producer in the nation.